The present invention relates to work platforms that are attached to lifts on vehicles. They are known as aerial baskets.
Aerial baskets are most commonly used by utility technicians for installation and servicing of electric power and telephone lines. Frequently, tree maintenance and similar jobs require the use of aerial baskets as well. Typically, a basket is mounted on a folding or telescoping lift attachment connected to the back of a medium sized truck. Most baskets are an open box in which a worker stands. The stand-up area is usually square in cross section, about forty inches deep, with each side being twenty-four inches long.
Current basket designs reflect a great concern for worker safety relating to electrocution and accidental fall hazards. Specific safety design standards have even been developed by the American National Standards Institute, Inc. [See, ANSI: American National Standard for Vehicle-Mounted Elevating and Rotating Work Platforms (1969).]
Although these developments have decreased the incidence of catastropic loss, professionals in the field have nonetheless reported significant increases in disabling low-back disorders among those workers regularly using aerial baskets. Applicant has determined that this is primarily because the structural limitations of current aerial baskets oblige the worker to stand in a restrictive work space. To perform manual handling tasks outboard of the standard basket, the worker must bend forward, stressing his spine (see FIG. 6). This posture helps cause the reported back injuries, for four main reasons.
First, the restricted position of one's legs within the basket eliminates any opportunity to achieve a potential biomechanical advantage obtainable through normal movement of the legs. Additionally, because the worker has to bend at the waist, instead of leaning forward, the lower spine is straightened out and loses its normal strengthening curvature. Also, the straightened spine causes the posterior muscles of the lower spine to remain stretched, which lessens their ability to produce force. Finally, the straightened spine simultaneously causes stretching and weakening of the ligaments surrounding the lower spine.
All of these deleterious effects result from the failure of prior aerial basket designs to incorporate modern ergonomic principles.
Accordingly, it is the primary object of the present invention to provide an improved aerial basket that is ergonomically structured to avoid the lower-back problems caused by the prior art.
It is a more specific object to provide an aerial basket which allows workers to retain the proper curvature of their spines while performing manual handling tasks outboard of the basket.
It is another specific object to provide an improved aerial basket which allows workers to achieve a biomechanical advantage that decreases stress to their lower backs while performing manual handling tasks outboard of the basket.
It is yet another object to provide an aerial basket which is commensurate with the above objects and allows workers to perform manual handling tasks throughout a circular operational work zone.
The above and other objects and advantages of this invention will become more readily apparent when the following description is read in conjunction with the accompanying drawings.